Thanks that chap, gathering round lake in America (5)
I believe the answer is:
tahoe
'lake in america' is the definition.
'tahoe' can be an answer for 'lake' (Lake Tahoe in the USA). I am not certain of the 'in america' bit.
'thanks that chap gathering round' is the wordplay.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'that chap' becomes 'he' ().
'gathering' is an insertion indicator (gather can mean to acquire or bring in).
'round' becomes 'o' (round can mean a round object).
'he' placed around 'o' is 'hoe'.
'ta'+'hoe'='TAHOE'
Can you help me to learn more?
(Other definitions for tahoe that I've seen before include "the Nevada/California border area" , "Lake in Sierra Nevada mountains" , "Lake/desert resort on the California-Nevada border" , "Mountain lake" , "Nevada/California lake" .)